Step 1

Preheat oven to 400°. Toss together sweet potatoes, olive oil, 1/8 teaspoon salt and pepper to taste on a small rimmed baking sheet. Spread into a single layer. Bake until potatoes are very tender, 35 to 45 minutes. Cool completely, about 20 minutes. Sweet potatoes can be roasted up to 2 days in advance and chilled in an airtight container.

Step 2

While potatoes are cooling, melt butter in a medium skillet over medium-low. Add shallots and cook, stirring often, until softened and golden brown, 12 to 15 minutes. Pour in apple cider vinegar and scrape up any brown bits that have stuck to the bottom of the pan. Add Brussels sprouts and remaining 1/8 teaspoon salt. Increase heat to medium and cook, stirring occasionally, until Brussels sprouts are bright green and barely softened, 5 to 8 minutes. Remove from heat and cool completely, about 30 minutes. Brussels sprouts mixture can be made up to 2 days in advance and chilled in an airtight container.

Step 3

Combine sweet potatoes, Brussels sprouts mixture, cheese, and sour cream in a medium bowl. Using your hands or a wooden spoon, stir together, mashing the potatoes until the mixture binds together. Season to taste with salt and pepper. Cover and chill for at least 1 hour or up to 2 days.

Step 4

Preheat oven to 450°F. Arrange half of the dough rounds on a lightly floured surface. Brush top of each round lightly with beaten egg. Spoon about 1 3/8 ounce (about 2 1/2 tablespoons) filling onto each pie crust round. Place remaining rounds on top of each pile of filling. Place your fingers under either side of each hand pie, while resting your thumbs on the top. Using your fingers, press the edges of the bottom round up to meet the top round and pinch together tightly to seal. Flip the hand pie over and crimp edges using a fork, dusting lightly in flour to prevent sticking. If desired, use the 4-inch round cutter to recut pie for clean edges. Repeat with remaining hand pies. Using a paring knife, cut a 1/2-inch slit in the top of each hand pie.

Step 5

Arrange hand pies on 2 parchment-lined baking sheets, spacing at least 1/2-inch apart. Brush tops and edges lightly with egg wash and sprinkle with evenly divided poppy seeds and flaky sea salt. Bake until hand pies are deeply golden brown, 25 to 35 minutes. Transfer pies to a wire rack to cool for 10 minutes. Serve warm with arugula salad, if desired. Cooled hand pies can be chilled in an airtight container for up to 2 days. —Lisa Ludwinski, Sister Pie, Detroit, MI